Method for producing organic electroluminescent device and film deposition apparatus

ABSTRACT

A method for producing an organic EL device in this disclosure includes the steps of providing an element substrate including a substrate and a plurality of organic EL devices arranged on the substrate; and forming a thin film encapsulation structure over the element substrate. The step of forming the thin film encapsulation structure includes the steps of forming a first inorganic barrier layer over the element substrate; condensing a photocurable resin on the first inorganic barrier layer; irradiating a plurality of selected regions of the photocurable resin with a laser beam to cure at least a part of the photocurable resin, thus to form a photocurable resin layer; removing an uncured part of the photocurable resin; and forming a second inorganic barrier layer, covering the photocurable resin layer, on the first inorganic barrier layer.

TECHNICAL FIELD

The present invention relates to a method for producing an organic ELdevice, specifically, a flexible organic EL device, and a filmdeposition apparatus. Typical examples of the organic EL device are anorganic EL display device and an organic EL illumination device.

BACKGROUND ART

Organic EL (Electro-Luminescence) display devices start being put intopractical use. One feature of an organic EL display device is beingflexible. An organic EL display device includes, in each of pixels, atleast one organic EL element (Organic Light Emitting Diode: OLED) and atleast one TFT (Thin Film Transistor) for controlling an electric currentto be supplied to each of the at least one OLED. Hereinafter, an organicEL display device will be referred to as an “OLED display device”. AnOLED display device including a switching element such as a TFT for eachof OLEDs is called an “active matrix OLED display device”. A substrateincluding the TFTs and the OLEDs which are formed thereon will bereferred to as an “element substrate”.

An OLED (especially, an organic light emitting layer and a cathodeelectrode material) is easily affected by moisture to be deterioratedand to cause display unevenness. One technology developed in order toprovide an encapsulation structure that protects the OLED againstmoisture while not spoiling the flexibility of the OLED display deviceis a thin film encapsulation (TFE) technology. According to the thinfilm encapsulation technology, inorganic barrier layers and organicbarrier layers are stacked alternately to allow thin films to provide asufficient level of water vapor barrier property. From the point of viewof moisture-resistance reliability of the OLED display device, such athin film encapsulation structure is typically required to have a WVTR(Water Vapor Transmission Rate) of 1×10⁻⁴ g/m²/day or less.

A thin film encapsulation structure used in OLED display devicescommercially available currently includes an organic barrier layer(polymer barrier layer) having a thickness of about 5 μm to about 20 μm.Such a relatively thick organic barrier layer also has a role offlattening a surface of the element substrate. However, such a thickorganic barrier layer involves a problem that the bendability of theOLED display device is limited.

There is also a problem that the mass-productivity is low. Therelatively thick organic barrier layer described above is formed by useof a printing technology such as an inkjet method, a microjet method orthe like. By contrast, the inorganic barrier layer is formed by a thinfilm deposition technology in a vacuum atmosphere (e.g., 1 Pa or less).The formation of the organic barrier layer by use of a printing methodis performed in the air or a nitrogen atmosphere, whereas the formationof the inorganic barrier layer is performed in vacuum. Therefore, theelement substrate is put into, and out of, a vacuum chamber during theformation of the thin film encapsulation structure, which decreases themass-productivity.

In such a situation, as disclosed in, for example, Patent Document 1, afilm deposition apparatus capable of producing an inorganic barrierlayer and an organic barrier layer continuously has been developed.

Patent Document 2 discloses a thin film encapsulation structureincluding a first inorganic material layer, a first resin member and asecond inorganic material layer provided on the element substrate inthis order. In this thin film encapsulation structure, the first resinmember is present locally, namely, in the vicinity of a protrudingportion of the first inorganic material layer (first inorganic materiallayer covering a protruding component). According to Patent Document 2,the first resin member is present locally, namely, in the vicinity ofthe protruding component, which may not be sufficiently covered with thefirst inorganic material layer. With such a structure, entrance ofmoisture or oxygen via the non-covered portion is suppressed. Inaddition, the first resin member acts as an underlying layer on whichthe second inorganic material layer is to be formed. Therefore, thesecond inorganic material layer is properly formed and properly covers aside surface of the first inorganic material layer with an expectedthickness. The first resin member is formed as follows. An organicmaterial heated and gasified to be mist-like is supplied onto an elementsubstrate maintained at room temperature or a lower temperature. As aresult, the organic material is condensed and put into drops on thesubstrate. The organic material in drops moves on the substrate by acapillary action or a surface tension to be present locally, namely, ata border between a side surface of the protruding portion of the firstinorganic barrier layer and a surface of the element substrate. Then,the organic material is cured to form the first resin member at theborder. Patent Document 3 also discloses an OLED display deviceincluding a similar thin film encapsulation structure.

Patent Document 4 discloses a film deposition apparatus usable toproduce an OLED display device.

CITATION LIST Patent Literature

Patent Document No. 1: Japanese Laid-Open Patent Publication No.2013-186971

Patent Document No. 2: WO2014/196137

Patent Document No. 3: Japanese Laid-Open Patent Publication No.2016-39120

Patent Document No. 4: Japanese Laid-Open Patent Publication No.2013-64187

SUMMARY OF THE INVENTION Technical Problem

The thin film encapsulation structure described in each of PatentDocuments 2 and 3 does not include a thick organic barrier layer, andtherefore, is considered to improve the bendability of the OLED displaydevice. In addition, since the inorganic barrier layer and the organicbarrier layer may be formed continuously, the mass-productivity is alsoimproved.

However, according to the studies made by the present inventor, anorganic barrier layer formed by the method described in Patent Document2 or 3 has a problem of not providing a sufficient level ofmoisture-resistance reliability.

In the case where an organic barrier layer is formed by use of aprinting method such as an inkjet method or the like, it is possible toform the organic barrier layer only in an active region on the elementsubstrate (the active region may also be referred to as an “elementformation region” or a “display region”) but not in a region other thanthe active region. In this case, in the vicinity of the active region(outer to the active region), there is a region where the firstinorganic material layer and the second inorganic material layer are indirect contact with each other, and the organic barrier layer is fullyenclosed by the first inorganic material layer and the second inorganicmaterial layer and is insulated from the outside of the first inorganicmaterial layer and the second inorganic material layer.

By contrast, according to the method for forming the organic barrierlayer described in Patent Documents 2 or 3, a resin (organic material)is supplied to the entire surface of the element substrate, and thesurface tension of the resin in a liquid state is used to put the resinat the border between the surface of the element substrate and the sidesurface of the protruding portion on the surface of the elementsubstrate. Therefore, the organic barrier layer may also be formed in aregion other than the active region (the region other than the activeregion may also be referred to as a “peripheral region”), namely, aterminal region where a plurality of terminals are located and a leadwire region where lead wires extending from the active region to theterminal region are formed. Specifically, an ultraviolet-curable resinis present locally, namely, at, for example, the border between thesurface of the element substrate and side surfaces of the lead wires orside surfaces of the terminals. In this case, an end of a part, of theorganic barrier layer, that is formed along the lead wires is notenclosed by the first inorganic barrier layer and the second inorganicbarrier layer, but is exposed to the air (ambient atmosphere).

The organic barrier layer is lower in the water vapor barrier propertythan the inorganic barrier layer. Therefore, the organic barrier layerformed along the lead wires acts as a route that leads the water vaporin the air into the active region.

The present invention provides a method for producing an organic ELdevice and a film deposition apparatus solving the above-describedproblems.

Solution to the Problem

In an illustrative embodiment, a method for producing an organic ELdevice of this disclosure includes the steps of providing an elementsubstrate including a substrate that includes an active region and aperipheral region outer to the active region and also including anelectrical circuit supported by the substrate, the electrical circuitincluding a plurality of EL elements formed on the active region and aback plane circuit for driving the plurality of organic EL elements, theback plane circuit including a plurality of lead wires each including aterminal on the peripheral region; and forming a thin film encapsulationstructure over the plurality of EL elements in the element substrate andon a part of the plurality of lead wires that is on the active region.The step of forming the thin film encapsulation structure includes thesteps of forming a first inorganic barrier layer over the elementsubstrate; condensing a photocurable resin in a liquid-state on thefirst inorganic barrier layer; irradiating a selected region of thephotocurable resin with a laser beam having a wavelength of 400 nm orshorter to cure at least a part of the photocurable resin, thus to forma photocurable resin layer while forming an opening in the photocurableresin layer on each of the plurality of lead wires; ashing a part of asurface of the photocurable resin layer to form an organic barrierlayer; and forming a second inorganic barrier layer, covering theorganic barrier layer, on the first inorganic barrier layer.

In an embodiment, in the step of condensing the photocurable resin inthe liquid state, the photocurable resin condensed on a flat portion ofthe first inorganic barrier layer has a thickness of 100 nm or greaterand 500 nm or less.

In an embodiment, the step of forming the organic barrier layer includesthe step of generating the laser beam from laser light emitted from atleast one semiconductor laser device.

In an embodiment, the substrate is a flexible substrate.

In an embodiment, the photocurable resin contains an acrylic monomer.

In an illustrative embodiment, a method for producing an organic ELdevice of this disclosure includes the steps of providing an elementsubstrate including a substrate and a plurality of organic EL devicesarranged on the substrate; and forming a thin film encapsulationstructure over the element substrate. The step of forming the thin filmencapsulation structure includes the steps of forming a first inorganicbarrier layer over the element substrate; condensing a photocurableresin on the first inorganic barrier layer; irradiating a plurality ofselected regions of the photocurable resin with a laser beam to cure atleast a part of the photocurable resin, thus to form a photocurableresin layer; removing an uncured part of the photocurable resin; andforming a second inorganic barrier layer, covering the photocurableresin layer remaining on the substrate, on the first inorganic barrierlayer.

In an embodiment, the plurality of regions of the photocurable resin areselected such that an active region of each of the organic EL devices isenclosed by a region where the first inorganic barrier layer and thesecond inorganic barrier layer are in contact with each other withouthaving an organic barrier layer therebetween.

In an embodiment, the plurality of regions of the photocurable resinrespectively cover the active regions of the organic EL devices, and areseparated from each other.

In an illustrative embodiment, a film deposition apparatus of thisdisclosure includes a chamber comprising a stage for supporting asubstrate; a material supply device for supplying a vapor-like ormist-like photocurable resin into the chamber; and a light source devicefor irradiating a plurality of selected regions of the substratesupported by the stage with a laser beam. The light source deviceincludes at least one semiconductor laser device for emitting the laserbeam; and an optical device for adjusting an intensity distribution, onthe substrate, of the laser beam emitted from the semiconductor laserdevice.

In an embodiment, the optical device includes at least one movablemirror for scanning the plurality of selected regions of the substratewith the laser beam.

In an embodiment, the light source device includes a plurality ofsemiconductor laser devices including the at least one semiconductorlaser device, and irradiates the plurality of selected regions of thesubstrate with a plurality of laser beams emitted from the plurality ofsemiconductor laser devices.

In an embodiment, the light source device includes a driving device formoving the plurality of semiconductor laser devices with respect to thesubstrate.

In an embodiment, the optical device adjusts the intensity distributionsuch that at least a part of the photocurable resin condensed on thesubstrate is not cured.

In an embodiment, the optical device includes a transmissive orreflective spatial light modulator modulating the intensitydistribution.

Advantageous Effects of Invention

An embodiment of the present invention provides a method for producingan organic EL device including a thin film encapsulation structure thatis improved in the mass-productivity and the moisture-resistancereliability, and a film deposition apparatus usable for the method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a schematic view showing a structure of a film depositionapparatus 200 usable to form an organic barrier layer 14.

FIG. 1B is a schematic view showing a state where laser beams 232 areemitted from a light source device 230 included in the film depositionapparatus 200.

FIG. 2 is an isometric view showing an example of positional arrangementof a plurality of regions (irradiation regions) 208, of an elementsubstrate 20, to be irradiated with the laser beam emitted from thelight source device 230.

FIG. 3 schematically shows an example of positional relationship betweenone OLED display device 100 formed at the element substrate 20 and theirradiation region 208 corresponding to this OLED display device 100.

FIG. 4 schematically shows how the plurality of irradiation regions 208are irradiated with the laser beams 232.

FIG. 5A is an isometric view showing an example in which the pluralityof irradiation regions 208 are irradiated with the plurality of laserbeams 232.

FIG. 5B is an isometric view showing an example in which the pluralityof irradiation regions 208 are irradiated with line-like laser beams232.

FIG. 6 is an isometric view schematically showing a basic structure of atypical semiconductor laser device.

FIG. 7 shows an example of structure in which an intensity distributionof the laser beam 232 is converted into a top hat-shaped intensitydistribution by use of a refraction-type optical device 260.

FIG. 8 shows an example in which a plurality of laser beams emitted froman array of a plurality of semiconductor laser devices 25 aresynthesized to form one laser beam 232 having an intensity distributionof a top hat shape.

FIG. 9 schematically shows an example in which one irradiation region208 is irradiated with the laser beam 232 from one light source device230.

FIG. 10 shows an example of structure in which the laser beam 232emitted from a fixed light source (e.g., one or a plurality ofsemiconductor laser devices 25) is reflected by a movable mirror 23 tosequentially irradiate the irradiation regions 208.

FIG. 11A is an isometric view schematically showing a state of amicro-mirror array 28.

FIG. 11B is an isometric view schematically showing another state of themicro-mirror array 28.

FIG. 12(a) is a schematic partial cross-sectional view of an activeregion of an OLED display device 100 in an embodiment according to thepresent invention, and FIG. 12(b) is a partial cross-sectional view of aTFE structure 10 formed on the OLED 3.

FIG. 13 is a schematic plan view showing a structure of an OLED displaydevice 100A in embodiment 1 according to the present invention.

FIG. 14(a) through FIG. 14(d) are each a schematic cross-sectional viewof the OLED display device 100A; FIG. 14(a) is a cross-sectional viewtaken along line 3A-3A′ in FIG. 13, FIG. 14(b) is a cross-sectional viewtaken along line 3B-3B′ in FIG. 13, FIG. 14(o) is a cross-sectional viewtaken along line 3C-3C′ in FIG. 13, and FIG. 14(d) is a cross-sectionalview taken along line 3D-3D′ in FIG. 13.

FIG. 15(a) is an enlarged view of a portion including a particle P inFIG. 14(a), and FIG. 15(b) is a schematic cross-sectional view of afirst inorganic barrier layer (SiN layer) covering the particle P.

FIG. 16A shows an example of “non-light exposure region S”, in which aninorganic barrier layer joint portion crossing lead wires 30A is to beformed.

FIG. 16B shows another example of “non-light exposure region S”, inwhich the inorganic barrier layer joint portion crossing lead wires 30Ais to be formed.

FIG. 16C shows still another example of “non-light exposure region S”,in which the inorganic barrier layer joint portion crossing lead wires30& is to be formed.

FIG. 17(a) and FIG. 17(b) are each a schematic cross-sectional viewshowing an example of TFT that may be included in the OLED displaydevice in embodiment 1 according to the present invention.

FIG. 18 provides schematic partial cross-sectional views of a TFEstructure 10 in an OLED display device in embodiment 2 according to thepresent invention; FIG. 18(a) is a cross-sectional view of a portionincluding a particle P, and FIG. 18(b) is a cross-sectional view of aportion including an inorganic barrier layer joint portion 3DBsubstantially enclosing an active region formed on an underlying surface(e.g., surface of the OLED 3) on which an for an organic barrier layer14D is to be formed.

FIG. 19 shows a cross-sectional SEM image of a first inorganic barrierlayer (SiN layer) covering a particle (silica sphere having a diameterof 1 μm) and also shows a planar SEM image thereof (bottom left).

FIG. 20 shows a cross-sectional SEM image of a TFE structure covering aparticle (silica sphere having a diameter of 2.15 μm) and also shows aplanar SEM image thereof (bottom left).

FIG. 21(a) through FIG. 21(c) are each a schematic cross-sectional viewshowing a step of forming the organic barrier layer 14D.

FIG. 22(a) through FIG. 22(a) are each a schematic cross-sectional viewshowing a step of forming a second inorganic barrier layer 16D.

FIG. 23 is a schematic cross-sectional view showing an organic barrierlayer 14Dd excessively ashed.

FIG. 24 is a schematic cross-sectional view showing the second inorganicbarrier layer 16D formed on the organic barrier layer 14Dd excessivelyashed.

DESCRIPTION OF EMBODIMENTS

In an illustrative embodiment, an “element substrate” in this disclosureincludes a substrate (base) including an active region and a peripheralregion outer to the active region, and also includes an electricalcircuit supported by the substrate. A typical example of the electricalcircuit includes a plurality of organic EL elements formed on the activeregion and a back plane circuit for driving the plurality of organic ELelements. The back plane circuit includes a plurality of lead wires eachincluding a terminal on the peripheral region.

Conventionally in order to form the organic barrier layer disclosed inPatent Document 2, a photocurable resin is condensed on an elementsubstrate on which a first inorganic barrier layer is formed, and thenthe entire surface of the element substrate is irradiated withultraviolet rays to cure the entirety of the photocurable resin. In aconventional film deposition apparatus, the ultraviolet rays are emittedfrom a high-pressure UV lamp.

By contrast, in an embodiment according to the present invention, arelatively thin photocurable resin in a liquid state is formed on asurface of an element substrate, and the relatively thin photocurableresin has a thickness of, for example, 500 nm or less on a flat portionof the element substrate. A plurality of selected regions of the elementsubstrate in this state are irradiated with a laser beam. As a result, apart, of the photocurable resin, that is condensed in a region otherthan the plurality of selected regions (light exposure regions) (namely,the part of the photocurable resin that is condensed in a non-lightexposure region) is not cured. Such an unnecessary part of thephotocurable resin is allowed to be selectively removed from the elementsubstrate. Therefore, the problem that a part of the organic barrierlayer forms a route that guides water vapor in the air into the activeregion is solved.

In an embodiment according to the present invention, between the firstinorganic barrier layer and the second inorganic barrier layer includedin the thin film encapsulation structure, the organic barrier layer(solid portion) is limited to be present in a selected region. Theentirety of the thin film encapsulation structure is substantiallydefined by the shapes of the first inorganic barrier layer and thesecond inorganic barrier layer. As seen in a direction normal to thesubstrate, the region where the organic barrier layer is present isinner to an outer circumference (profile) of the thin film encapsulationstructure.

In an embodiment according to the present invention, a coherent laserbeam emitted from, for example, a semiconductor laser device is used.Therefore, the linearity of the light beam is high, and selectiveexposure to light is realized without a mask being put into closecontact with the element substrate. Thus, even in the case where theelement substrate is located in the film deposition apparatus in a statewhere a photocurable resin in a liquid state is formed on a surface ofthe element substrate, a desired region of the element substrate isselectively exposed to light in this state. There is a conventionalproblem that if the element substrate having a photocurable resin in aliquid state (in a wet state) formed thereon is moved or vibrated beforethe photocurable resin is exposed to light or cured, the photocurableresin is moved from the position of condensation and the organic barrierlayer is not formed at a desired position. Such a problem is avoided inan embodiment according to the present invention.

FIG. 1A schematically shows an example of basic structure of a filmdeposition apparatus 200 preferably usable for a method for producing anorganic EL device according to the present invention. The filmdeposition apparatus 200 is used to form an organic barrier layerincluded in a thin film encapsulation structure.

The film deposition apparatus 200 shown in the figure includes a chamber210 and a partition wall 234 dividing an inner space of the chamber 210into two spaces. In one of the spaces in the chamber 210 demarcated bythe partition wall 234, a stage 212 and a shower plate 220 are located.In the other space demarcated by the partition wall 234, a light sourcedevice (ultraviolet ray irradiation device) 230 is located. The innerspace of the chamber 210 is controlled to have a predetermined pressure(vacuum degree) and a predetermined temperature.

The stage 212 has a top surface that supports an element substrate 20.The top surface may be cooled down to, for example, −20° C. As describedbelow in detail, the element substrate 20 includes, for example, aflexible substrate and a plurality of organic EL devices located on theflexible substrate. The element substrate 20 is placed on the stage 212in a state where the first inorganic barrier layer (not shown in FIG. 1)included in the thin film encapsulation structure is formed on theelement substrate 20. The first inorganic barrier layer is an underlyinglayer on which an organic barrier layer is to be formed.

A gap 224 is formed between the shower plate 220 and the partition wall234. The gap 224 may have a size of, for example, 100 mm or greater and1000 mm or less in a vertical direction. The shower plate 220 has aplurality of through-holes 222. The plurality of through-holes 222 eachact as a material supply nozzle. A photocurable resin (in a liquidstate), supplied in a predetermined amount to the gap 224, is suppliedin a vapor or mist state to the element substrate 20 in the chamber 210via the plurality of through-holes 222. As necessary, the photocurableresin is heated. A typical example of the photocurable resin is anacrylic monomer. In the example shown in the figure, a vapor-like ormist-like acrylic monomer 26 p is attached to, or contacts, the firstinorganic barrier layer over the element substrate 20. An acrylicmonomer 26 is supplied from a container 202 into the chamber 210 at apredetermined flow rate. The container 202 is supplied with the acrylicmonomer 26 via a pipe 206 and also is supplied with nitrogen gas from apipe 204. The flow rate of the acrylic monomer supplied to the container202 is controlled by a mass flow controller 208. A material supplydevice includes the shower plate 220, the pipe 204, the mass flowcontroller 208 and the like.

The light source device 230 is configured to irradiate a plurality ofselected regions of the element substrate 20 supported by the stage 212with laser beams 232. FIG. 18 is a schematic view showing a state wherethe laser beams 232 are emitted from the light source device 230. Asdescribed above, the space in which the light source device 230 islocated in the chamber 210 of the film deposition apparatus 200 isseparated, by the partition wall 234, from the space supplied with thematerial gas. The partition wall 234 and the shower plate 220 are formedof a material transmitting the laser beams 232 (e.g., quartz). Thestructure of the film deposition apparatus in this disclosure is notlimited to the example shown here.

Hereinafter, with reference to FIG. 2 through FIG. 1B, an example ofstructure of the light source device 230 will be described in detail.

FIG. 2 is an isometric view showing an example of positional arrangementof a plurality of regions (irradiation regions) 208, of the elementsubstrate 20, to be irradiated with the laser beam emitted from thelight source device 230. Rectangular regions enclosed by the dashed lineare respectively the irradiation regions 208, which are separated fromeach other. FIG. 2 shows 24 irradiation regions 208 arranged in fourrows by six columns as an example. The number and the positionalarrangement of the irradiation regions 20S are not limited to theexample shown in the figure. The shape and the size of each of theirradiation regions 208 are not limited to the example shown in thefigure.

FIG. 3 schematically shows an example of positional relationship betweenone OLED display device 100 formed at the element substrate 20 and theirradiation region 208 corresponding to the OLED display device 100. Atop part of FIG. 3 shows a plan view showing a layout, and a bottom partof FIG. 3 shows a cross-sectional structure.

In the example shown in FIG. 3, the OLED display device 100 includes asubstrate 1, a circuit (back plane circuit) 2 supported by the substrate1, and an OLED 3 formed on the circuit 2. The element substrate 20 shownin FIG. 2 is on a stage before the substrate 1 is divided into aplurality of the substrates 1 of the OLED display devices 100 as shownin FIG. 3. The substrates 1 of the plurality of OLED display devices 100are each a part of one continuous base included in the element substrate20.

The entirety of the circuit 2 and the OLED 3 shown in FIG. 3 is coveredand sealed with the thin film encapsulation (TFE) structure 10. As shownin FIG. 3, one irradiation region 208 is larger than a region where thecircuit 2 and the OLED 3 are formed, but is smaller than a region wherethe TFE structure 10 is formed. Therefore, in an intermediate regionfrom an outer edge of the irradiation region 20 s to an outer edge ofthe region where the TFE structure 10 is formed (such an intermediateregion is included in a non-light exposure region), a photocurable resinsuch as the acrylic monomer 26 or the like, even if being condensed, isnot cured, and thus an organic barrier layer is not formed. As a result,in the “intermediate region”, the first inorganic barrier layer and thesecond inorganic barrier layer included in the TFE structure 10 are indirect contact with each other. As described below, in thisspecification, a portion where the first inorganic barrier layer and thesecond inorganic barrier layer are in direct contact with each other maybe referred to as an “inorganic barrier layer joint portion”. In theexample shown in FIG. 3, the “inorganic barrier layer joint portion”includes a portion extending in a length direction and having a width tand a portion extending in a width direction and having a width Gy, andencloses the circuit 2 and the OLED 3.

The OLED display device 100 shown in FIG. 3 includes a plurality of leadwires 30 connecting the circuit 2 with, for example, a driver integratedcircuit (IC). In this disclosure, the circuit 2 and the plurality oflead wires will be collectively referred to as “electrical circuitry”.In the example shown in FIG. 3, four lead wires 30 are shown for thesake of simplicity. In actuality, the number of the lead wires 30 is notlimited to the number in this example. The lead wires 30 do not need toextend linearly, but may include a bent portion and/or a branchedportion.

The lead wires 30 extend from the circuit 2 to the outside of theabove-described “intermediate region”. Namely, a part of each of thelead wires 30 is covered with the TFE structure 10, but the remainingpart of each of the lead wires 30 (at least an end acting as a pad,namely, a terminal) is not covered with the TFE structure 10. The partof each lead wire 30 that is not covered with the TFE structure 10 mayelectrically contact and may be connected with, for example, a terminalof the driver integrated circuit (IC).

FIG. 4 schematically shows how the plurality of irradiation regions 208are irradiated with the laser beams 232 (maskless projection lightexposure). As shown in FIG. 3, the plurality of irradiation regions 208each cover a region of the corresponding OLED display device 10 wherethe organic barrier layer needs to be formed. Oppositely described, aregion of each OLED display device 100 where the organic barrier layerdoes not need to be formed is not irradiated with the laser beams 232.It is not required that a region outer to the irradiation regions 208(non-light exposure region) is not irradiated with the laser beams 232at all. If the radiation dose provided by the laser beams 232 to acertain region is lower than a level required to cure the photocurableresin, the certain region is a “non-light exposure region”, and is not aregion selected to be exposed to light (not an irradiation region). Inorder to cure an acrylic monomer layer having a thickness of, forexample, 100 to 500 nm with ultraviolet rays (having a wavelength of,for example, 370 to 390 nm), a radiation dose of, for example, 100 to200 mJ/cm² is required. In this case, in a region other than theselected regions (irradiation regions 208), the radiation dose providedby the laser beams 232 may be suppressed to, for example, 50 mJ/cm² orless.

FIG. 4 shows that the plurality of irradiation regions 208 areirradiated with the plurality of laser beams 232 at the same time. Theplurality of irradiation regions 208 do not need to be irradiated withthe plurality of laser beams 232 at the same time. The plurality ofirradiation regions 208 may be irradiated with a laser beam 232sequentially. The laser beams 232 shown in FIG. 4 are each a bundle ofparallel light beams. In actuality, the laser beams 232 may each beconverged or diverged. The angle of incidence of the laser beam 232 withrespect to the element substrate 20 is not limited to beingperpendicular. In the case where the laser beam 232 is incidentobliquely, the cross-sectional shape of the laser beam 232 may beappropriately corrected in accordance with the angle of incidence suchthat the irradiation regions 208 have the shape shown in FIG. 3.

FIG. 5A is an isometric view schematically showing an example in whichthe plurality of irradiation regions 208 arranged in a line areirradiated with a plurality of laser beams 232. In this figure,coordinate axes including an X axis, a Y axis and a Z axis perpendicularto each other are shown for reference. In this example, the light sourcedevice 230 is configured to emit the laser beam 232 from each of aplurality of light emitting portions arranged in a line in an X-axisdirection. The plurality of light emitting portions may each be onesemiconductor laser device or an array of a plurality of semiconductorlaser devices. In the example shown in FIG. 5A, the light source device230 is supported so as to be movable at least in a Y-axis direction, andis driven by, for example a motor (not shown). The position of the lightsource device 230 may be changed by a driving device such as the motoror the like, so that different irradiation regions 208, among theplurality of irradiation region 208, may be sequentially irradiated withthe laser beams 232 at a plurality of different positions.

A plurality of the light source devices 230 each having the structureshown in FIG. 5k may be arranged in the Y-axis direction.

FIG. 5B shows an example in which one irradiation region 208 irradiatedwith the laser beam 232 extends in the X-axis direction so as to extendacross a plurality of the OLED display device 100. Non-light exposureregions located between adjacent irradiation regions 20S extend likeslits in the X-axis direction. The plurality of irradiation regions 208are arranged in a pattern that is set such that the non-light exposureregions completely cross the lead wires 30. In the case where thephotocurable resin is not formed on the flat portion, or in the casewhere the organic barrier layer formed on the flat portion is removed byashing, the flat portion with no lead wire 30 may be irradiated with thelaser beam. A reason for this is that the organic barrier layer may beremoved from the flat portion in a later step. In such a case, althoughone irradiation region 20S extends across the plurality of OLED displaydevices 100 as shown in FIG. 5B, the organic barrier layer is notpresent in the vicinity of the active region of each of the OLED displaydevices 100. The organic barrier layer is not needed in the vicinity ofthe active region.

FIG. 6 is an isometric view schematically showing a basic structure of atypical semiconductor laser device. A semiconductor laser device 25shown in FIG. 6 includes a facet 254 including an emitter 256 foremitting the laser beam 232. A stripe-shaped electrode 252 is providedon a top surface of the semiconductor laser device 25. A bottom surfaceelectrode (not shown) is provided on a bottom surface of thesemiconductor laser device 25. When an electric current of a levelexceeding a lasing threshold flows between the stripe-shaped electrode252 and the bottom surface electrode, laser oscillation occurs and thelaser beam 232 is emitted from the emitter 256.

The structure shown in FIG. 6 is merely a typical example of thesemiconductor laser device 25, and is schematically shown in order tosimplify the description. In the example shown in FIG. 6, the facet 254of the semiconductor laser device 25 is parallel to an X-Y plane.Therefore, the laser beam 232 is emitted in a Z-axis direction from theemitter 256. An optical axis of the laser beam 232 is parallel to theZ-axis direction. A divergence of the laser beam 232 in the Y-axisdirection is defined by angle θf, and a divergence of the laser beam 232in the X-axis direction is defined by angle θs. Because of thediffraction effect, angle θf is usually larger than θs, and across-section of the laser beam 232 (portion having an intensity of apredetermined value or larger) is elliptical. Therefore, in thisembodiment, the laser beam 232 emitted from the semiconductor laserdevice 25 is not used as it is to expose the photocurable resin, but theintensity distribution of the laser beam 232 is adjusted by an opticaldevice such as a lens, an optical fiber or the like.

FIG. 7 shows an example of structure in which the intensity distributionof the laser beam 232 is converted into a top hat-shaped intensitydistribution by use of a refraction-type optical device 260. The opticaldevice 260 causes different types of refraction in an X-Z plane and aY-Z plane from each other, and thus shapes the laser beam 232 such thatthe laser beam 232 has an intensity distribution matched to theirradiation region 20S shown in FIG. 3. FIG. 7 schematically shows anexample of intensity distribution L in a cross-section (parallel to theX-Y plane) perpendicular to the optical axis (parallel to the Z-axis) ofthe laser beam 232. The intensity distribution L has a portion in whichthe intensity is almost uniform regardless of the position (has a flatportion). Such a shape of intensity distribution may be referred to asthe “top hat shape”. In the case where the cross-section of the laserbeam having such a top hat-shaped intensity distribution matches theshape of the active region of the circuit 2 and the OLED 3 as shown inFIG. 3, selective exposure to light is performed efficiently.

An example of semiconductor laser device that emits a laser beam havinga wavelength in an ultraviolet region (400 nm or shorter) may be a laserdiode of product No. NDU7216 produced by Nichia Corporation. This laserdiode provides a laser beam having a wavelength of 370 to 390 nm at acontinuous wave (CW) output of 200 milliwatts (mW). A laser diode moduleof product No. NUU102E produced by Nichia Corporation provides acontinuous wave laser beam having a wavelength of 370 to 390 nm at anoutput of 3 watts (W). Even in the case where a laser beam having a CWoutput of 3 watts (W) is emitted as being diverged to a region of 100cm², a radiation dose of 300 mJ/cm^(k) is realized in 10 seconds.Therefore, even if the laser beam is emitted for a short time asrequired for mass-production, a radiation dose of a level sufficient tocure a relatively thin photocurable resin layer (having a thickness of100 to 500 nm on a flat portion of the first inorganic barrier) isprovided.

The irradiation regions 20S do not need to be irradiated with the laserbeam 232 emitted from one semiconductor laser device 25. FIG. 8 shows anexample in which a plurality of laser beams emitted from an array of aplurality of the semiconductor laser devices 25 are synthesized to formone laser beam 232 having an intensity distribution of a top hat shape.The plurality of semiconductor laser devices 25 do not need to emit thelaser beams with the same optical output. The semiconductor laserdevices 25 do not need to be arranged at an equal interval. Thepositions, orientations, outputs, wavelengths and the like of thesemiconductor laser devices 25 may be appropriately adjusted so as tooptimize the intensity distribution of the laser beam 23 on the elementsubstrate. FIG. 8 omits the optical device such as a lens, a mirror orthe like for the sake of simplicity. A known optical device may be usedto realize a desired intensity distribution. The optical device mayinclude a light-blocking mask having a slit or an opening transmitting apart of the laser beam 232. The laser beam is highly coherent and formsa precise light irradiation pattern defined by a narrow slit or opening.

FIG. 9 schematically shows an example in which one irradiation region208 is irradiated with the laser beam 232 from one light source device230. In actuality, a plurality of the light source devices 230 may belocated so as to face all the irradiation regions 208. Alternatively,one or a plurality of source devices 230 may move to sequentiallyirradiate all the irradiation regions 20S with the laser beam 232.

FIG. 10 shows an example of structure in which the laser beam 232emitted from a fixed light source (e.g., one or a plurality ofsemiconductor laser devices 25) is reflected by a movable mirror 23 tosequentially irradiate the irradiation regions 208. The movable mirror23 may be, for example, a polygon mirror or a Galvano mirror. Themovable mirror 23 may include a non-reflective region 23B absorbing orscattering a part of the laser beam 232. The non-reflective region 233adjusts the cross-sectional shape and the intensity distribution of thelaser beam 232 on the element substrate 20. The orientation of themovable mirror 23 may be changed by, for example, a biaxial actuator(not shown), and thus may reflect the laser beam 232 in any direction.As described above, in order to realize the shape of the irradiationregion 238 shown in FIG. 3 while the orientation of the movable mirror23 is changed, it is preferred that the cross-sectional shape of thelaser beam 232 is appropriately corrected in accordance with the angleof incidence (keystone correction). Such a correction is realized byputting an optical element (not shown) on an optical path and performingbeam shaping. The number of the movable mirror(s) 23 and the number ofthe light source(s) are not limited to one but may be two or more.

The movable mirror 23 may be a reflective spatial light modulator (e.g.,liquid crystal panel). Such a spatial light modulator dynamicallychanges the cross-sectional shape and the intensity distribution of thelaser beam 232 on the element substrate 20.

A reflective or transmissive spatial light modulator may be used,instead of the movable mirror 23, to convert laser light emitted fromthe semiconductor laser device 25 into the laser beam 232 having anarbitrary intensity distribution. With such a structure, it is madepossible to irradiate the entirety of, or a part of, the elementsubstrate 20 with the laser beam 232 having an arbitrary intensitydistribution. Keystone correction is made easily. In addition, it ismade possible to easily change the shape, the size or the location ofthe irradiation regions 208 in accordance with the type of the elementsubstrate 20. In the case where a transmissive spatial light modulatoris used, the spatial light modulator may be located, for example,between a laser light source of the light source device 230 shown inFIG. 5A, FIG. 5B or FIG. 9 and the element substrate 20. The lightsource device 230 acts as a projector including a laser light sourceproviding ultraviolet laser light.

The movable mirror 23 may be a micro-mirror array. FIG. 11A and FIG. 11Bare isometric views schematically showing different states of amicro-mirror array 28. The micro-mirror array 28 includes a plurality ofmicroscopic mirrors 281 arranged two-dimensionally, an actuator thatchanges the orientation of each of the microscopic mirrors 281, and acircuit that drives the actuator. The orientation or each or themicroscopic mirrors 28M may be adjusted to spatially modulate the laserbeam incident on the micro-mirror array 28, so that any region of theelement substrate 20 is irradiated with the laser beam. The orientationof each of the microscopic mirrors 28M may be changed to scan the topsurface of the element substrate 20 by the laser beam 232. The use ofthe micro-mirror array 28 allows the shape, the size and the locationsof the irradiation regions 20S to be changed easily in accordance withthe type of the element substrate 20.

With the film deposition apparatus 200 including the light source device230 described above, it is made possible to perform a step of condensingthe photocurable resin on the first inorganic barrier layer over theelement substrate 20 and a step of irradiating the plurality of selectedregions of the photocurable resin with the laser beam and curing atleast a part of the photocurable resin to form a photocurable resinlayer. The light source device usable for the film deposition apparatusaccording to the present invention is not limited to having theabove-described structure. Any projection-type or scanning-type lightsource device that emits a laser beam in a wavelength that cures aphotocurable resin is usable for the film deposition apparatus accordingto the present invention.

In embodiments described below, a step of removing a part, of thephotocurable resin, that is not exposed to light and thus is not curedis performed, and then, a step of forming the second inorganic barrierlayer, covering the photocurable resin layer remaining on the substrate,on the first inorganic barrier layer is performed. In this manner, thethin film encapsulation structure is formed.

(Example of Structure of the Display Device)

Hereinafter, an example of structure of a display device that may beproduced in an embodiment according to the present invention will bedescribed. An embodiment according to the present invention is notlimited to the following embodiment.

First, with reference to FIG. 12(a) and FIG. 12(b), a basic structure ofan OLED display device 100 as an example of display device produced inan embodiment according to the present invention will be described. FIG.12(a) is a schematic partial cross-sectional view of an active region ofthe OLED display device 100 in an embodiment according to the presentinvention. FIG. 12(b) is a partial cross-sectional view of a TFEstructure 10 formed on an OLED 3. An OLED display device in each ofembodiment 1 and embodiment 2 described below has basically the samestructure, and may be the same as the OLED display device 100 except forthe structure of the TFE structure 10.

The OLED display device 100 includes a plurality of pixels, and each ofthe pixels includes at least one organic EL element (OLED). Herein, astructure corresponding to one OLED will be described for the sake ofsimplicity.

As shown in FIG. 12(a), the OLED display device 100 includes a flexiblesubstrate (hereinafter, may be referred to simply as a “substrate”) 1, acircuit (back plane circuit) 2 that is formed on the substrate 1 andincludes a TFT, the OLED 3 formed on the circuit 2, and the TFEstructure 10 formed on the OLED 3. The OLED 3 is, for example, of a topemission type. An uppermost portion of the OLED 3 is, for example, a topelectrode or a cap layer (refractive index adjusting layer). An optionalpolarization plate 4 is located on the TFE structure 10.

The substrate 1 is, for example, a polyimide film having a thickness of15 μm. The circuit 2 including the TFT has a thickness of, for example,4 μm. The OLED 3 has a thickness of, for example, 1 μm. The TFEstructure 10 has a thickness of, for example, 1.5 μm or less.

FIG. 12(b) is a partial cross-sectional view of the TFE structure 10formed on the OLED 3. A first inorganic barrier layer (e.g., SiN layer)12 is formed immediately on the OLED 3. An organic barrier layer (e.g.,acrylic resin layer) 14 is formed on the first inorganic barrier layer12. A second inorganic barrier layer (e.g., SiN layer) 16 is formed onthe organic barrier layer 14.

The first inorganic barrier layer 12 and the second inorganic barrierlayer 16 are each, for example, an SiN layer having a thickness of 400μm. The organic barrier layer 14 is, for example, an acrylic resin layerhaving a thickness less than 100 ram. The first inorganic barrier layer12 and the second inorganic barrier layer 16 independently have athickness of 200 nm or greater and 1000 nm or less. The organic barrierlayer 14 has a thickness of 50 nm or greater and less than 200 nm. Inthe case where a particle described below is present on the firstinorganic barrier layer 12, the thickness of the organic barrier layer14 is increased locally, namely, in the vicinity of the particle and maybecome approximately the same as the thickness of the second inorganicbarrier layer. The TFE structure 10 has a thickness of preferably 400 nmor greater and less than 2 μm, and more preferably of 400 nm or greaterand less than 1.5 μm.

The TEE structure 10 is formed to protect an active region (see activeregion R1 in FIG. 13) of the OLED display device 100. At least in theactive region, there are the first inorganic barrier layer 12, theorganic barrier layer 14 and the second inorganic barrier layer 16formed in this order on the OLED 3, with the first inorganic barrierlayer 12 being closest to the OLED 3. The organic barrier layer 14 isnot present as a film covering the entirety of the active region, butincludes an opening. A part of the organic barrier layer 14 other thanthe opening, namely, a part actually formed of an organic film, will bereferred to as a “solid portion”. The “opening” (may be referred to alsoas a “non-solid portion”) does not need to be enclosed by the solidportion, but may have a cutout or the like. In the opening, the firstinorganic barrier layer 12 and the second inorganic barrier layer 16 arein direct contact with each other. The opening included in the organicbarrier layer 14 includes at least an opening formed to enclose theactive region, and the active region is fully enclosed by a portionwhere the first inorganic barrier layer 12 and the second inorganicbarrier layer 16 are in direct contact with each other (“inorganicbarrier layer junction portion”). A planar shape of the organic barrierlayer 14 having such a structure is defined by a portion in which aregion where a photocurable resin is present in a condensed state and aregion selectively exposed to a laser beam (Irradiation region) overlapeach other. Namely, even if the region where no photocurable resin ispresent is irradiated with a laser beam, the organic barrier layer 14 isnot formed in such a region. Even in the region where the photocurableresin is present, the organic barrier layer 14 is not formed unless sucha region is irradiated with a laser beam of a necessary radiation dose.In addition, the planar shape of the organic barrier layer 14 may bedecreased in the size by ashing performed on the organic barrier layer14 as necessary.

Embodiment 1

With reference to FIG. 13 through FIG. 15, a method for producing anOLED display device in embodiment 1 according to the present inventionwill be described.

FIG. 13 is a schematic plan view of an OLED display device 100A inembodiment 1 according to the present invention. The OLED display device100A includes a flexible substrate 1, a circuit (back plane circuit) 2formed on the flexible substrate 1, a plurality of OLEDs 3 formed on thecircuit 2, and a TFE structure 10A formed on the OLEDs 3. A layerincluding an array of the plurality of OLEDs 3 may be referred to as an“OLED layer 3”. The circuit 2 and the OLEDs 3 may share at least onecomponent. An optional polarization plate (see reference numeral 4 inFIG. 12) may further be located on the TFE structure 10A. In addition, alayer having a touch panel function may be located between the TFEstructure 10A and the polarization plate. Namely, the OLED displaydevice 100A may be altered to a display device including an on-cell typetouch panel.

The circuit 2 includes a plurality of TFTs (not shown), and a pluralityof gate bus lines (not shown) and a plurality of source bus lines (notshown) each connected to either one of the plurality of TFTs (notshown). The circuit 2 may be a known circuit that drives the pluralityof OLEDs 3. The plurality of OLEDs 3 are each connected with either oneof the plurality of TFTs included in the circuit 2. The OLEDs 3 may beknown OLEDs.

The OLED display device 100A further includes a plurality of terminals38A located in a peripheral region R2 outer to the active region (regionenclosed by the dashed line in FIG. 13) R1, where the plurality of OLEDs3 are located, and a plurality of lead wires 30A connecting each of theplurality of terminals 38A and either one of the plurality of gate buslines or either one of the plurality of source bus lines to each other.The TFE structure 10A is formed on the plurality of OLEDs 3 and on apart, of the plurality of lead wires 30A, that is in the active regionR1. Namely, the TFE structure 10A covers the entirety of the activeregion R1 and is selectively formed on the part of the plurality of leadwires 30A that is in the active region R1. Neither a part, of the leadwires 30A, closer to the terminals 38A, nor the terminals 38A, arecovered with the TFE structure 10A.

Hereinafter, an example in which the lead wires 30A and the terminals38A are integrally formed in the same conductive layer will bedescribed. Alternatively, the lead wires 30A and the terminals 38A maybe formed in different conductive layers from each other (the lead wires30A and the terminals 38A may have a stack structure).

Now, with reference to FIG. 14(a) through FIG. 14(d), the TFE structure10A of the OLED display device 100A will be described. FIG. 14(a) showsa cross-section taken along line 3A-3A′ in FIG. 13. FIG. 14(b) shows across-section taken along line 3B-3B′ in FIG. 13. FIG. 14(a) shows across-section taken along line 3C-3C′ in FIG. 13. FIG. 14(d) shows across-section taken along line 3D-3D′ in FIG. 13. FIG. 14(d) is across-sectional view of a region where the TFE structure 10A is notformed.

As shown in FIG. 14(a), the TFE structure 10A includes a first inorganicbarrier layer 12A formed on the OLEDs 3, an organic barrier layer 14A incontact with the first inorganic barrier layer 12A, and a secondinorganic barrier layer 16A in contact with the organic barrier layer14A. The first inorganic barrier layer 12A and the second inorganicbarrier layer 16A are each, for example, an SiN layer, and areselectively formed in a predetermined region so as to cover the activeregion R1 by plasma CVD using a mask.

The organic barrier layer 14A may be formed by, for example, the methoddescribed in Patent Document 2. For example, a vapor-like or mist-likephotocurable resin (e.g., an organic material such as acrylic monomer orthe like) is supplied, in a chamber, onto an element substratemaintained at room temperature or a lower temperature. The photocurableresin is condensed on the element substrate and put into an liquidstate. The photocurable resin in this state is allowed to be locatedlocally, namely, at a border between a side surface of a protrudingportion and a flat portion of the first inorganic barrier layer 12 by acapillary action or a surface tension of the photocurable resin. Then, aselected region of the photocurable resin is irradiated with, forexample, an ultraviolet laser beam to be partially cured, so that asolid portion of the organic barrier layer (e.g., acrylic resin layer)14A is formed at the border in the vicinity of the protruding portion inthe selected region. The organic barrier layer 14A formed by this methodsubstantially includes no solid portion in the flat portion. Regardingthe method for forming the organic barrier layer, the disclosure ofPatent Document 2 is incorporated herein by reference.

FIG. 14(a) is a cross-sectional view taken along line 3A-3A′ in FIG. 13,and shows a portion including a particle P. The particle P is amicroscopic dust particle generated during the production of the OLEDdisplay device, and is, for example, a microscopic piece of brokenglass, a metal particle or an organic particle. Such a particle isespecially easily generated in the case where mask vapor deposition isused.

As shown in FIG. 14(a), the organic barrier layer (solid portion) 14Amay be formed only in the vicinity of the particle P. A reason for thisis that the acrylic monomer supplied after the first inorganic barrierlayer 12A is formed is condensed and present locally, namely, in thevicinity of a surface of the first inorganic barrier layer 12A on theparticle P. There is the opening (non-solid portion) of the organicbarrier layer 14A on the flat portion of the first inorganic barrierlayer 12A.

Now, with reference to FIG. 15(a) and FIG. 15(b), a structure of theportion including the particle P will be described. FIG. 15(a) is anenlarged view of the portion including the particle P in FIG. 14(a), andFIG. 15(b) is a schematic cross-sectional view of the first inorganicbarrier layer (e.g., SiN layer) covering the particle P.

As shown in FIG. 15(b), in the case where the particle P (having adiameter of, for example, 1 μm or longer) is present, the firstinorganic barrier layer may have a crack (void) 12Ac. As describedbelow, this is considered to be caused by impingement of an SiN layer12Aa growing from a surface of the particle P and an SiN layer 12Abgrowing from a flat portion of a surface of the OLED 3. In the casewhere such a crack 12Ac is present, the barrier property level of theTFE structure 10A is decreased.

As shown in FIG. 15(a), in the TFE structure 10A of the OLED displaydevice 100A, the organic barrier layer 14A is formed to fill the crack12Ac in the first inorganic barrier layer 12A, and a surface of theorganic barrier layer 14A couples a surface of the first inorganicbarrier layer 12Aa on the particle P and a surface of the firstinorganic barrier layer 12Ab on the flat portion of the OLED 3 to eachother continuously and smoothly. Therefore, the first inorganic barrierlayer 12A on the particle P and the second inorganic barrier layer 16Aformed on the organic barrier layer 14A have no void and are fine. Ascan be seen, even in the case where the particle is present, the organicbarrier layer 14A retains the barrier property level of the TFEstructure 10A.

Now, with reference to FIG. 14(b) and FIG. 14(c), a specific example ofthe TFE structure 10A on the lead wires 30A will be described. FIG.14(b) is a cross-sectional view taken along line 3B-3B′ in FIG. 13, andshows a cross-section of portions 32A of the lead wires 30A. Theportions 32A of the lead wires 32 are located in the irradiation regionto be irradiated with the laser beam. By contrast, FIG. 14(c) is across-sectional view taken along line 3C-3C′ in FIG. 13, and shows across-section of portions 34A of the lead wires 30A. The portions 34A ofthe lead wires 30A are located outer to the irradiation region to beirradiated with the laser beam (located in the non-light exposureregion).

The lead wires 30A are patterned in, for example, the process in whichthe gate bus lines or the source bus lines are patterned. Therefore, inthis example, the gate bus lines and the source bus lines formed in theactive region R1 have the same cross-sectional structure as that of theportions 32A and the portions 34A of the lead wires 30A. Thecross-sectional shape of the lead wires 30A is not limited to theexample shown in FIG. 14.

The OLED display device 100A in an embodiment according to the presentinvention is preferably usable for, for example, a small- ormedium-sized high-definition smartphone or tablet terminal. For a small-or medium-sized (e.g., 5.7 inches) high-definition (e.g., 500 ppi) OLEDdisplay device, it is preferred that the wires (including the gate buslines and the source bus lines) in the active region R1 have across-section of a shape close to a rectangle, in a direction parallelto the line width direction in order to have a sufficiently lowresistance with a limited line width. In the meantime, the active regionR1 of the OLED display device 100A is substantially enclosed by theinorganic barrier layer joint portion where the first inorganic barrierlayer 12A and the second inorganic barrier layer 16A are in directcontact with each other. Therefore, the organic barrier layer 14A doesnot act as a route that guides moisture into the active region R1, andthus moisture does not enter the active region R1 of the OLED displaydevice.

Referring to FIG. 14(b), the organic barrier layer (solid portion) 14 ispresent between the first inorganic barrier layer 12A and the secondinorganic barrier layer 16A, at the side surface of each of the portions32A of the lead wires 30A.

By contrast, referring to FIG. 14(c), at the side surface of each of theportions 34A of the lead wires 30A, the organic barrier layer (solidportion) 14 is not present, and the first inorganic barrier layer 12Aand the second inorganic barrier layer 16A are in direct contact witheach other (namely, the inorganic barrier layer joint portion isformed). On the flat portion, the organic barrier layer (solid portion)14A is not formed. Therefore, in a cross-section taken along line 3C-3C′in FIG. 13, the lead wires 30A are covered with the inorganic barrierlayer joint portion where the first inorganic barrier layer 12A and thesecond inorganic barrier layer 16A are in direct contact with eachother.

For this reason, as described above, it does not occur that the organicbarrier layer formed along the lead wires acts as a route that guideswater vapor in the air into the active region. From the point of view ofthe moisture-resistance reliability, it is preferred that the length ofthe portions 34A of the lead wires 30A, namely, the size (width) of theinorganic barrier layer joint portion measured in a direction in whichthe lead wires 30A extend, is at least 0.01 mm. There is no specificupper limit on the width of the inorganic barrier layer joint portion.However, even if the width exceeds 0.1 mm, the effect of improving themoisture-resistance reliability is substantially saturated. A widthlonger than 0.1 mw merely increases the width of the frame portion.Therefore, the width is preferably 0.1 mm or shorter, and may be, forexample, 0.05 mm or shorter. In a conventional TFE structure in whichthe organic barrier layer is formed by an inkjet method, an organicbarrier layer joint portion having a width of about 0.5 mm to about 1.0mm is provided in consideration of the variance in the position of anedge of the organic barrier layer. By contrast, in an embodimentaccording to the present invention, the width of the inorganic barrierlayer joint portion may be 0.1 mm or shorter. This decreases the widthof the frame portion of the organic EL display device.

Now, FIG. 14(d) will be referred to. FIG. 14(d) is a cross-sectionalview of the region where the TFE structure 10A is not formed. Portions36K of the lead wires 30A shown in FIG. 14(d) are located outer to theirradiation region to be irradiated with the laser beam (located in thenon-light exposure region). Therefore, the organic barrier layer 14A isnot formed on a lowest portion of a side surface of each of the portions36A. Thus, the organic barrier layer (solid portion) 14A is not presenton a side surface of the portions 34A of the lead wires 30A or a sidesurface of the terminals 38A. The organic barrier layer 14A is notpresent on the flat portion, either.

As described above, the formation of the organic barrier layer 14Aincludes a step of supplying a vapor-like or mist-like photocurableresin (e.g., acrylic monomer). Therefore, the photocurable resin is notallowed to be selectively condensed only in a predetermined region,unlike the first inorganic barrier layer 12A or the second inorganicbarrier layer 16A. For this reason, with a conventional method ofexposing the entire surface of the substrate to ultraviolet rays, theorganic barrier layer (solid portion) 14A may be formed also in a regionwhere the organic barrier layer (solid portion) 14A is not necessary. Bycontrast, in this embodiment, a plurality of selected regions areirradiated with a laser beam. This suppresses formation of the organicbarrier layer (solid portion) 14A in stepped portions caused by the leadwires.

FIG. 168, FIG. 16B and FIG. 16C each show an example of “non-lightexposure region S”, in which the inorganic barrier layer joint portioncrossing the lead wires 30A is to be formed. In each of these figures,the white region is the “non-light exposure region S”. The non-lightexposure region S extending like a slit merely needs to cross the leadwires 30A completely, but does not need to cover the entirety of thelead wires 30A. The shape and the size of the non-light exposure regionS are not limited to those shown here. The non-light exposure region Smay have any of various shapes and any of various sizes with which amoisture entrance route provided by the organic barrier layer 14A, whichmay be formed along the lead wires 30A, is blocked.

Now, with reference to FIG. 17, an example of TFT usable in the OLEDdisplay device 100A, and an example of lead wire and an example ofterminal formed by use of a gate metal layer and a source metal layerused to form the formation of the TFT, will be described.

For a small- or medium-sized high-definition OLED display device, a lowtemperature polycrystalline silicon (referred to simply as “LTPS”) TFTor an oxide TFT (e.g., four-component-based (In—Ga—Zn—O-based) oxide TFTcontaining In (indium), Ga (gallium), Zn (zinc) and O) (oxygen)), whichhas a high mobility, is preferably used. Structures of, and methods forproducing, the LTPS-TFT and the In—Ga—Zn—O-based TFT are well known andwill be merely briefly described below.

FIG. 17(a) is a schematic cross-sectional view of an LTPS-TFT 2 _(p)T.The TFT 2 _(p)T may be included in the circuit 2 of the OLED displaydevice 100A. The LTPS-TFT 2 _(p)T is a top gate-type TFT.

The TFT 2 _(p)T is formed on a base coat 2 _(p)p on the substrate 1(e.g., polyimide film). Although not described above, it is preferredthat a base coat formed of an inorganic insulating material is formed onthe substrate 1.

The TFT 2 _(p)T includes a polycrystalline silicon layer 2 _(P)se formedon the base coat 2 _(p)p, a gate insulating layer 2 _(p)gi formed on thepolycrystalline silicon layer 2 _(p)se, a gate electrode 2 _(P)g formedon the gate insulating layer 2 _(p)gi, an interlayer insulating layer 2_(p)i formed on the gate electrode 2 _(p)G, and a source electrode 2_(p)ss and a drain electrode 2 _(p)sd formed on the interlayerinsulating layer 2 _(p)i. The source electrode 2 _(p)ss and the drainelectrode 2 _(p)sd are respectively connected with a source region and adrain region of the polycrystalline silicon layer 2 _(p)se in contactholes formed in the interlayer insulating layer 2 _(p)i and the gateinsulating layer 2 _(p)gi.

The gate electrode 2 _(p)g is contained in the gate metal layercontaining the gate bus lines, and the source electrode 2 _(p)ss and thedrain electrode 2 _(p)sd are contained in the source metal layercontaining the source bus lines. The gate metal layer and the sourcemetal layer are used to form the lead wire and the terminal.

The TFT 2 _(p)T is formed, for example, as follows.

As the substrate 1, for example, a polyimide film having a thickness of15 μm is prepared.

The base coat 2 _(p)p (SiO₂ film: 250 nm/SiN film: 50 nm/SiO₂ film: 500nm (top layer/middle layer/bottom layer)) and an a-Si film (40 nm) areformed by plasma CVD.

The a-Si film is subjected to dehydrogenation (e.g., annealed at 450° C.for 180 minutes).

The a-Si film is crystallized to form a polycrystalline-silicon byexcimer laser annealing (ELA).

The a-Si film is patterned by a photolithography step to form an activelayer (semiconductor island).

A gate insulating film (SiO₂ film: 50 nm) is formed by plasma CVD.

A channel region of the active layer is doped with (B⁺).

The gate metal layer (Mo: 250 nm) is formed by sputtering and patternedby a photolithography step (including a dry etching step) (to form thegate electrode 2 _(p)g, the gate bus lines, and the like).

A source region and a drain region of the active layer are doped with(P⁺).

Activation annealing (e.g., annealing at 450° C. for 45 minutes) isperformed. As a result, the polycrystalline silicon layer 2 _(p)se isformed.

An interlayer insulating film (e.g., SiO₂ film: 300 nm/SiN film: 300 nm(top layer/bottom layer)) is formed by plasma CVD.

The contact holes are formed in the gate insulating film and theinterlayer insulating film by dry etching. As a result, the interlayerinsulating layer 2 _(p)i and the gate insulating layer 2 _(p)gi areformed.

The source metal layer (Ti film: 100 nm/Al film: 300 nm/Ti film: 30 nm)is formed by sputtering and patterned by a photolithography step(including a dry etching step) (to form the source electrode 2 _(p)ss,the drain electrode 2 _(p)sd, the source bus lines, and the like).

FIG. 17(b) is a schematic cross-sectional view of an In—Ga—Zn—O-basedTFT 2 _(o)T. The TFT 2 _(o)T may be included in the circuit 2 of theOLED display device 100A. The TFT 2 _(o)T is a bottom gate-type TFT.

The TFT 2 _(o)T is formed on a base coat 2 _(o)p on the substrate 1(e.g., polyimide film). The TFT 2 _(o)T includes a gate electrode 2_(o)g formed on the base coat 2 _(o)p, a gate insulating layer 2 _(o)giformed on the gate electrode 2 _(o)g, an oxide semiconductor layer 2_(o)se formed on the gate insulating layer 2 _(o)gi, and a sourceelectrode 2 _(o)ss and a drain electrode 2 _(o)sd respectively formed ona source region and a drain region of the oxide semiconductor layer 2_(o)se. The source electrode 2 _(o)ss and the drain electrode 2 _(o)sdare covered with an interlayer insulating layer 2 _(o)i.

The gate electrode 2 _(o)g is contained in the gate metal layercontaining the gate bus lines, and the source electrode 2 _(o)ss and thedrain electrode 2 _(o)sd are contained in the source metal layercontaining the source bus lines. The gate metal layer and the sourcemetal layer may be used to form the lead wire and the terminal.

The TFT 2 _(o)T is formed, for example, as follows.

As the substrate 1, for example, a polyimide film having a thickness of15 μm is prepared.

The base coat 2 _(o)p (SiO₂ film: 250 nm/SiN_(x) film: 50 nm/SiO₂ film:500 nm (top layer/middle layer/bottom layer)) is formed by plasma CVD.

The gate metal layer (Cu film: 300 nm/Ti film: 30 nm (top layer/bottomlayer)) is formed by sputtering and patterned by a photolithography step(including a dry etching step) (to form the gate electrode 2 _(o)g, thegate bus lines, and the like).

A gate insulating film (SiO₂ film: 30 nm/SiN_(x) film: 350 nm (toplayer/bottom layer)) is formed by plasma CVD.

An oxide semiconductor film (In—Ga—Z—O-based semiconductor film: 100 nm)is formed by sputtering and patterned by a photolithography step(including a wet etching step) to form an active layer (semiconductorisland).

The source metal layer (Ti film: 100 nm/Al film: 300 nm/Ti film: 30 nm(top layer/medium layer/bottom layer)) is formed by sputtering andpatterned by a photolithography step (including a dry etching step) (toform the source electrode 2 _(o)ss, the drain electrode 2 _(o)sd, thesource bus lines, and the like).

Activation annealing (e.g., annealing at 300° C. for 120 minutes) isperformed. As a result, the oxide semiconductor layer 2 _(o)se isformed.

After this, the interlayer insulating layer 2 _(o)i (e.g., SiN_(x) film:300 nm/SiO₂ film: 300 nm (top layer/bottom layer)) is formed by plasmaCVD as a protective film.

Embodiment 2

In the formation of the organic barrier layer 14A described inembodiment 1, a photocurable resin such as an acrylic monomer or thelike is located locally, namely, in a stepped portion. A method forproducing an OLED display device in embodiment 2 described belowincludes a step of forming a resin layer (e.g., acrylic resin layer)also on at least a part of the flat portion and partially ashing theresin layer to form an organic barrier layer. First, the thickness ofthe resin layer to be formed is adjusted (to, for example, less than 100nm), the irradiation region to be irradiated with the laser beam isselected, and/or ashing conditions (including time) are adjusted. Inthis manner, an organic barrier layer of any of various forms may beformed. Namely, the organic barrier layer 14A included in the OLEDdisplay device 100A described in embodiment 1 may be formed, or anorganic barrier layer (solid portion) substantially covering a part of,or the entirety of, the flat portion may be formed. In the case wherethe organic barrier layer has a large area size, an effect of improvinga bending resistance is provided. In the following, an OLED displaydevice including a TFE structure that includes an organic barrier layer(solid portion) covering a part of, or the entirety of, a flat portion,and a method for producing the same, will be mainly described. Thestructure of the element substrate before the TFE structure is formed,especially, the structures of the lead wires and the terminals and thestructure of the TFT, may be any of the structures described inembodiment 1.

FIG. 18(a) is a schematic partial cross-sectional view of a TFEstructure 10D in an OLED display device in embodiment 2 according to thepresent invention, and shows a portion including a particle P. Asdescribed above with reference to FIG. 15(b), in the case where theparticle P is present, a first inorganic barrier layer 12D may have acrack (void) 12Dc. Based on a cross-sectional SEM image shown in FIG.19, this is considered to be caused by impingement of an SiN layer 12Dagrowing from a surface of the particle P and an SiN layer 12Db growingfrom a flat portion of a surface of the OLED 3. In the case where such acrack 12Dc is present, the barrier property level of the TFE structure10D is decreased. The SEM image shown in FIG. 19 is of a sample formedas follows. In a state where a silica sphere having a diameter of 1 μmas the particle P is located on a glass substrate, an SiN film is formedby plasma CVD. The cross-section shown here is not taken along a planepassing the center of the particle P. An outermost surface of the sphereis a carbon layer (C-depo) provided for protection at the time ofprocessing the cross-section. As can be seen, even the presence of arelatively small silica sphere having a diameter of 1 μm causes thecrack (void) 12Dc in the SiN layer 12D.

In the TFE structure 10D of the OLED display device in embodiment 2, asshown in FIG. 18(a), an organic barrier layer 14Dc is formed to fill thecrack 12Dc in the first inorganic barrier layer 12D and a portionoverhanging the particle P. Therefore, the barrier property level isretained by a second inorganic barrier layer 16D. This is confirmed by across-sectional SEM image shown in FIG. 20. In FIG. 20, no interfaceappears in a portion where the second inorganic barrier layer 16D isformed directly on the first inorganic barrier layer 12D. However, inthe schematic view, the first inorganic barrier layer 12D and the secondinorganic barrier layer 16D are shown with different patterns ofhatching for clear illustration.

The cross-sectional SEM image shown in FIG. 20 is of a sample formed asfollows. In a state where a silica sphere having a diameter of 2.15 μmis located on a glass substrate like in the case of the cross-sectionalSEM image shown in FIG. 19, the TFE structure 10D is formed. As can beseen from a comparison between FIG. 20 and FIG. 19, although thediameter of the particle P shown in FIG. 20 is about twice the diameterof the particle P shown in FIG. 19, the SiN film formed on the acrylicresin layer is fine with no void. Separately, another sample formed asfollows is observed. Like in the case of FIG. 19, an SiN film is formedby plasma CVD so as to cover particles P (silica spheres havingdiameters of 2.15 μm and 4.6 μm), an acrylic resin layer is formed asthe organic barrier layer 14D, and then another SiN film is formed byplasma CVD. With this sample also, it has been confirmed by an SEMobservation that the SiN film formed on the acrylic resin layer is finewith no void.

As described below, the organic barrier layer 14D shown in FIG. 18(a) isformed of, for example, an acrylic resin. A film formed by curing, withlight (e.g., ultraviolet rays), an acrylic monomer (acrylate) having aviscosity of about 1 to about 100 mPa·s at room temperature (e.g., 25′C)is especially preferable. An acrylic monomer having such a low viscosityeasily permeates the crack 12Dc and the portion overhanging the particleP. An acrylic resin has a high visible light transmittance and thus ispreferably used for an OLED display device of a top emission type. Theacrylic monomer is mixed with a photoinitiator as necessary. Thephotosensitive wavelength is adjustable in accordance with the type ofthe photoinitiator. Instead of the acrylic monomer, another photocurableresin is usable. A preferable photocurable resin is anultraviolet-curable resin from the point of view of the reactivity orthe like. A preferable laser beam to be used to irradiate the acrylicmonomer has a wavelength in a UV-A region, namely, a wavelength of 315nm or longer and 400 nm or shorter, among wavelengths in a nearultraviolet region (200 nm or longer and 400 nm or shorter).Alternatively, a laser beam having a wavelength of 300 nm or longer andshorter than 315 nm may be used. Still alternatively, a photocurableresin that is cured when being irradiated with a visible light laserbeam in a range of bluish purple to blue having a wavelength of 400 nmor longer and 450 nm or shorter may be used.

A surface of the organic barrier layer 14Dc filing the crack 12Dc andthe portion overhanging the particle P couples a surface of the firstinorganic barrier layer 12Da on the particle P and a surface of anorganic barrier layer 14Db formed on the flat portion of the surface ofthe OLED 3 to each other continuously and smoothly. Therefore, thesecond inorganic barrier layer 16D formed on the first inorganic barrierlayer 12D on the particle P and on the organic barrier layer 14D is finewith no void.

A surface 14Ds of the organic barrier layer 14D is oxidized by ashing,and thus is hydrophilic and highly adhesive with the second inorganicbarrier layer 16D.

In order to improve the bending resistance, it is preferred that theorganic barrier layer 14D is ashed so as to remain on substantially theentire surface of the first inorganic barrier layer 12D except for thefirst inorganic barrier layer 12Da, namely, the protruding portionformed on the particle P. It is preferred that the organic barrier layer14Db on the flat portion has a thickness of 10 nm or greater.

Patent Documents 2 and 3 each describe a structure in which an organicbarrier layer is locally located. As a result of various experimentsperformed by the present inventor, it has been found that the organicbarrier layer 14D may be formed on substantially the entirety of theflat portion of the first inorganic barrier layer 12D, namely, onsubstantially the entire surface of the first inorganic barrier layer12D except for the first inorganic barrier layer 12Da, namely, theprotruding portion. It is preferred from the point view of the bendingresistance that the organic barrier layer 14D has a thickness of 10 nmor greater.

The organic barrier layer 14D provided between the first inorganicbarrier layer 12D and the second inorganic barrier layer 16D improvesthe adhesiveness between the layers in the TFE structure 10D.Especially, the surface of the organic barrier layer 14D is oxidized andthus is highly adhesive with the second inorganic barrier layer 16D.

In the case where the organic barrier layer 14Db is formed on theentirety of the flat portion (i.e., in the case where the organicbarrier layer 14D does not include an opening 14Da), when an externalforce is applied to the OLED display device, the stress (or the strain)caused in the TFE structure 10D is uniformly dispersed. As a result,breakage (especially, breakage of the first inorganic barrier layer 12Dand/or the second inorganic barrier layer 16D) is suppressed. Theorganic barrier layer 14D present substantially uniformly while being inclose contact with the first inorganic barrier layer 12D and the secondinorganic barrier layer 16D is considered to act to disperse andalleviate the stress. As can be seen, the organic barrier layer 14D alsoprovides an effect of improving the bending resistance of the OLEDdisplay device.

It should be noted that in the case where the organic barrier layer 14Dhas a thickness of 200 nm or greater, the bending resistance may bedecreased. Therefore, it is preferred that the thickness of the organicbarrier layer 14D is less than 200 nm.

The formation of the organic barrier layer 14D is completed afterashing. Ashing may be performed non-uniformly in the plane;specifically, a part of the organic barrier layer 14Db formed on theflat portion may be removed in the entire thickness thereof to exposethe surface of the first inorganic barrier layer 12D. In this step, theorganic barrier layer 14D is controlled such that the organic barrierlayer (solid portion) 14Db formed on the flat portion of the OLED 3,among various parts of the organic barrier layer 14D, has an area sizelarger than that of the opening 14Da. Namely, the organic barrier layer14D is controlled such that the solid portion 14Db has an area size thatexceeds 50% of the area size of the organic barrier layer (including theopening) 14D on the flat portion. It is preferred that the area size ofthe solid portion 14Db is 80% or larger of the area size of the organicbarrier layer 14D on the flat portion. Nonetheless, it is preferred thatthe area size of the solid portion 14Db does not exceed about 90% of thearea size of the organic barrier layer on the flat portion. In otherwords, it is preferred that the organic barrier layer 14D on the flatportion includes the opening 14Da having an area size in total of about10% of the area size thereof. The opening 14Da provides an effect ofsuppressing the first inorganic barrier layer 12D and the organicbarrier layer 14D from being delaminated from each other at theinterface thereof and of suppressing the organic barrier layer 14D andthe second inorganic barrier layer 16D from being delaminated from eachother at the interface thereof. In the case where the area size of theopening 14Da is 80% or larger and 90% or smaller of the area size of theorganic barrier layer 14D on the flat portion, an especially highbending resistance is provided.

In the case where the organic barrier layer 14D is formed on theentirety of the flat portion, the organic barrier layer 14D on the flatportion acts as a route by which moisture enters the inside of the OLEDdisplay device, which declines the moisture-resistance reliability ofthe OLED display device. In order to prevent this, as shown in FIG.18(b), the OLED display device in embodiment 2 includes an inorganicbarrier layer joint portion 3DB substantially enclosing the activeregion. The inorganic barrier layer joint portion 3DB is defined by thenon-light exposure region not to be irradiated with the laser beam.

In the inorganic barrier layer joint portion 3DB, the photocurable resinthat is present in a pre-light exposure stage is not irradiated with thelaser beam, and thus is not cured and selectively removed. Therefore, inthe inorganic barrier layer joint portion 3DB, the opening 14Da of theorganic barrier layer 14D is present but the solid portion 14Db is notpresent. Namely, in the inorganic barrier layer joint portion 3DB, thefirst inorganic barrier layer 12D and the second inorganic barrier layer16D are in direct contact with each other. The OLED display device inembodiment 2 includes the organic barrier layer 14D on the flat portion,but the active region is fully enclosed by the inorganic barrier layerjoint portion 3DB. Therefore, the OLED display device has a high levelof moisture-resistance reliability.

With reference to FIG. 21 and FIG. 22, a step of forming the organicbarrier layer 14D and the second inorganic barrier layer 16D,especially, a step of ashing, will be described. FIG. 21 shows a step offorming the organic barrier layer 14D, and FIG. 22 shows a step offorming the second inorganic barrier layer 16D.

As schematically shown in FIG. 21(a), the first inorganic barrier layer12D covering the particle P on the surface of the OLED 3 is formed, andthen the organic barrier layer 14D is formed on the first inorganicbarrier layer 12D. The organic barrier layer 14D is formed, for example,as follows. A vapor-like or mist-like acrylic monomer is condensed on acooled element substrate, and then is irradiated with light (e.g.,ultraviolet rays) to be cured. An acrylic monomer having a low viscositymay be used, so that the acrylic monomer permeates the crack 12Dc formedin the first inorganic barrier layer 12D.

In the example shown in FIG. 21(a), an organic barrier layer 14Dd isformed on the first inorganic barrier layer 12Da on the particle P.However, depending on the size or the shape of the particle P or thetype of the acrylic monomer, the acrylic monomer may not be deposited(or attached) on the first inorganic barrier layer 12Da on the particleP, or may be deposited (or attached) merely in trace amount. The organicbarrier layer 14D may be formed by use of, for example, the filmdeposition apparatus 200. The organic barrier layer 14D is adjusted tohave an initial thickness of 100 nm or greater and 500 nm or less on theflat portion. Immediately after being formed, the organic barrier layer14D has a surface 14Dsa that is smoothly continuous and hydrophobic. Forthe sake of simplicity, the organic barrier layer before the ashingbears the same reference sign.

Next, as shown in FIG. 21(b), the organic barrier layer 14D is ashed.The ashing may be performed by use of a known plasma ashing device, aknown photoexcitation ashing device, or a known UV ozone ashing device.For example, plasma ashing using at least one type of gas among N₂O, O₂and O₃, or a combination of such plasma ashing and ultraviolet rayirradiation, may be performed. In the case where an SiN film is formedby CVD as the first inorganic barrier layer 12D and the second inorganicbarrier layer 16D, N₂O is used as a material gas. Therefore, use of N₂Ofor the ashing provides an advantage that the device is simplified.

In the case where the ashing is performed, the surface 14Ds of theorganic barrier layer 14D is oxidized and thus is modified to behydrophilic. In addition, the surface 14D of the organic barrier layer14 is shaved almost uniformly and extremely tiny concaved and convexedportions are formed, and thus the surface area size of the surface 14Dsis enlarged. The effect of enlarging the surface area size provided bythe ashing is greater for the surface of the organic barrier layer 14Dthan for the first inorganic barrier layer 12D formed of an inorganicmaterial. Since the surface 14Ds of the organic barrier layer 14D ismodified to be hydrophilic and the surface area size of the surface 14Dsis enlarged, the adhesiveness of the organic barrier layer 14D with thesecond inorganic barrier layer 16D is improved.

As the ashing is continued, as shown in FIG. 21(c), the opening 14Da isformed in a part of the organic barrier layer 14D.

As the ashing is still continued, as the organic barrier layer 14 shownin FIG. 15(a), the organic barrier layer 14Dc is left only in the crack12Dc in the first inorganic barrier layer 12D and in the vicinity of theportion overhanging the particle P. In this state, the surface of theorganic barrier layer 14Dc couples a surface of the first inorganicbarrier layer 12Da on the particle P and the surface of the flat portionof the OLED 3 to each other continuously and smoothly.

In order to improve the adhesiveness between the first inorganic barrierlayer 12D and the organic barrier layer 14D, the surface of the firstinorganic barrier layer 12D may be ashed before the organic barrierlayer 14D is formed.

Now, with reference to FIG. 22, a structure obtained after the secondinorganic barrier layer 16D is formed on the organic barrier layer 14Dwill be described.

FIG. 22(a) schematically shows a structure obtained after the surface14Dsa of the organic barrier layer 14D shown in FIG. 21(a) is ashed tobe oxidized and modified to the hydrophilic surface 14Ds and then thesecond inorganic barrier layer 16D is formed. In this example, thesurface 14Dsa of the organic barrier layer 14D is slightly ashed, andthus an organic barrier layer 14Dd remains on the first inorganicbarrier layer 12Da on the particle P. Alternatively, there may be a casewhere the organic barrier layer 14D is not formed (or does not remain)on the first inorganic barrier layer 12Da on the particle P.

As shown in FIG. 22(a), the second inorganic barrier layer 16D formed onthe organic barrier layer 14D has no void and has a high adhesivenesswith the organic barrier layer 14D.

As shown in FIG. 22(b) and FIG. 22(c), the second inorganic barrierlayer 16D formed on the organic barrier layer 14D shown in FIG. 21(b)and FIG. 21(a), each have no void and have a high adhesiveness with theorganic barrier layer 14D. Even if the organic barrier layer 14D on theflat portion of the OLED 3 is completely removed, as long as the surfaceof the organic barrier layer 14Dc couples the surface of the firstinorganic barrier layer 12Da on the particle P and the surface of theflat portion of the OLED 3 to each other continuously and smoothly, thesecond inorganic barrier layer 16D has no void and has a highadhesiveness with the organic barrier layer 14D.

As shown in FIG. 22(b), the organic barrier layer 14D may be ashed so asto remain as a thin film on the entire surface of the first inorganicbarrier layer 12D except for the first inorganic barrier layer 12Da,namely, the protruding portion formed on the particle P. As describedabove, it is preferred from the point view of the bending resistancethat the thickness of the organic barrier layer 14Db on the flat portionis 10 nm or greater and less than 200 nm.

Ashing may be performed non-uniformly in the plane; specifically, a partof the organic barrier layer 14D formed on the flat portion may beremoved in the entire thickness thereof to expose the surface of thefirst inorganic barrier layer 12D. In addition, the material and thesize of the particle P are varied, and therefore, there may be a portionhaving a structure shown in FIG. 22(a) or FIG. 15(a). It is preferredthat the organic barrier layer 14D is controlled such that even if apart of the organic barrier layer 14D formed on the flat portion isremoved in the entire thickness thereof, the organic barrier layer(solid portion) 14Db formed on the flat portion of the OLED 3, amongvarious parts of the organic barrier layer 14D, has an area size largerthan that of the opening 14Da. As described above, it is preferred thatthe area size of the solid portion 14Db is 80% or larger, and does notexceed about 90%, of the area size of the organic barrier layer 14D onthe flat portion.

In the case where the organic barrier layer 14D is ashed excessively, asshown in FIG. 23, the organic barrier layer 14Db formed on the flatportion of the OLED 3 is completely removed and also the size of theorganic barrier layer 14Dd filling the crack 12Dc formed by the particleP is decreased. Thus, the organic barrier layer 14D does not act tosmooth the surface of the underlying layer on which the second inorganicbarrier layer 16D is to be formed. As a result, as shown in FIG. 24, avoid 16Dc is formed in the second inorganic barrier layer 16D, whichdecreases the barrier property level of the TFE structure. Even if thevoid 16Dc is not formed, if a recessed portion 16Dd having a sharp angleis formed at a surface of the second inorganic barrier layer 16D, thestress is easily concentrated at the recessed portion and thus a crackis easily formed by an external force.

In an experiment using a convex lens formed of silica (diameter: 4.6 μm)as the particle P, there was a case where the organic barrier layer wasexcessively etched at an end of the silica convex lens, and as a result,the thickness of the second inorganic barrier layer was partially madeexcessively thin. In such a case, even if no void is formed in thesecond inorganic barrier layer, a crack may be formed in the secondinorganic barrier layer when an external force is applied to the TFEstructure during or after the production of the OLED display device.

An external force may be applied to the TFE structure 10 in thefollowing cases. For example, at the time of peeling off the flexiblesubstrate 1 of the OLED display device from a glass substrate as asupport substrate, a bending stress is applied to the OLED displaydevice including the TFE structure 10. At the time of bending the OLEDdisplay device along a predetermined curve shape during the productionof a curved display, a bending stress is applied to the TFE structure10. Needless to say, in the case where the OLED display device as afinished product is used as a flexible device (for example, the OLEDdisplay device is used as being folded, bent or rolled), variousstresses are applied to the TFE structure 10 while the user uses theOLED display device.

In order to prevent this, it is preferred that the ashing conditions areadjusted such that more than 50% of the organic barrier layer formed onthe flat portion of the OLED 3 remains (such that the area size of theorganic barrier layer (solid portion) 14Db is larger than the area sizeof the opening 14Da). The organic barrier layer (solid portion) 14Dbremaining on the flat portion of the OLED 3 is more preferably 80% orlarger, and still more preferably about 90%. Nonetheless, it is furtherpreferred that the opening 14Da is also present with the area size ofabout 10% because the opening 14Da provides an effect of suppressing thefirst inorganic barrier layer 12D and the organic barrier layer 14D frombeing delaminated from each other at the interface thereof and ofsuppressing the organic barrier layer 14D and the second inorganicbarrier layer 16D from being delaminated from each other at theinterface thereof. As shown in FIG. 22(a) through FIG. 22(a), thesurface of the second inorganic barrier layer 16D, formed on the organicbarrier layer 14D remaining in an appropriate amount, does not have aportion having an angle of 90 degrees or smaller (see the recessedportion 16Dd shown in FIG. 24). Therefore, even if an external force isapplied, the concentration of a stress is suppressed.

A method for producing the OLED display device in embodiment 2 accordingto the present invention includes a step of providing, in a chamber, theOLED 3 and the first inorganic barrier layer 12D formed thereon, a stepof supplying a vapor-like or mist-like photocurable resin (e.g., acrylicmonomer) into the chamber, a step of condensing the photocurable resinon the first inorganic barrier layer 12D to form a liquid film, a stepof irradiating the liquid film of the photocurable resin with light toform a photocurable resin layer (layer of the cured resin), and a stepof partially ashing the photocurable resin layer to form the organicbarrier layer 14D.

An ultraviolet-curable resin is preferably used as the photocurableresin. Thus, in the following, an example of using theultraviolet-curable resin will be described. Alternatively, a visiblelight-curable resin may be used as long as a light source that emitslight having a predetermined wavelength capable of curing a photocurableresin is used.

The film deposition apparatus 200 shown in FIG. 1A and FIG. 13B isusable to form the organic barrier layer 14 in, for example, thefollowing manner. The following example is one typical example ofconditions used to form the TFE structure 10 and a sample shown in theSEM photograph as a trial.

The acrylic monomer 26 p is supplied to the chamber 210. The acrylicmonomer 26 p is introduced into the gap 224, passes the through-holes222 of the shower plate 220, and is supplied to the element substrate 20on the stage 212. The element substrate 20 has been cooled down to, forexample, −15° C. on the stage 212. The acrylic monomer 26 p is condensedon the first inorganic barrier layer 12D on the element substrate tobecome a liquid film. The supply amount of the acrylic monomer 26 p andthe temperature and the pressure (vacuum degree) in the chamber 21 maybe controlled to adjust the deposition rate of the acrylic monomer(liquid). For example, the acrylic monomer may be deposited at a rate of500 nm/min. Therefore, a layer of the acrylic monomer having a thicknessof about 200 nm may be formed within about 24 seconds.

The above-mentioned conditions may be controlled such that the acrylicmonomer is located locally, namely, only in the vicinity of theprotruding portion, like in the method for forming the organic barrierlayer in embodiment 1.

As the acrylic monomer, any of various known acrylic monomers is usable.A plurality of acrylic monomers may be mixed together. For example, abifunctional monomer and a trifunctional or higher-levelmulti-functional monomer may be mixed. An oligomer may be mixed. It ispreferred that the acrylic monomer is adjusted to have a viscosity ofabout 1 to about 100 mPa·s at room temperature (e.g., 25° C.). Theacrylic monomer may be mixed with a photointiator when necessary.

After this, the gas in the chamber 210 is discharged, and the vapor-likeor mist-like acrylic monomer 26 p is removed. Then, as shown in FIG. 1,the acrylic monomer on the first inorganic barrier layer 12D issubjected to selective exposure to the laser beam 232 and thus is cured.In the case where the above-described high-output laser diode module isused, the selective exposure to light is completed within an irradiationtime of about 10 seconds.

As described above, the tact time of the step of forming the organicbarrier layer 14D is about 34 seconds, which provides a very highmass-productivity.

The first inorganic barrier layer 12D is formed, for example, asfollows. The inorganic barrier layer 12D having a thickness of 400 nmmay be formed by plasma CVD using SiH₄ gas and N₂O gas, at a filmdeposition rate of 400 nm/min, in a state where, for example, thetemperature of the substrate (OLED 3) on which the first inorganicbarrier layer 12D is to be formed is controlled to be 80° C. or lower.The inorganic barrier layer thus formed has a refractive index of 1.84and a 400 nm visible light transmittance of 90% (thickness: 400 nm). Thefilm stress has an absolute value of 50 MPa.

The organic barrier layer 14D is ashed by, for example, plasma ashingusing N₂O gas. The ashing is performed in a chamber for ashing. Theashing rate is, for example, 500 nm/min. The ashing is performed forabout 22 seconds such that when the organic barrier layer 14D having athickness of 200 nm is formed as described above, the thickness (maximumvalue) of the organic barrier layer (solid portion) 14Db on the flatportion is about 20 nm.

The conditions in the above step may be controlled to form the organicbarrier layer 14A shown in FIG. 14(a) and FIG. 14(b). The organicbarrier layer 14D on the lead wires is thinner than the remainingportion of the organic barrier layer 14D. Therefore, the organic barrierlayer 14D on the lead wires may be removed, and more than 50% of theorganic barrier layer 14D on the flat portion may be left.

After the ashing, N₂O gas is discharged, and the resultant body oflayers is transported into a CVD chamber in which the second inorganicbarrier layer 16D is to be formed. The second inorganic barrier layer16D is formed under, for example, the same conditions as for the firstinorganic barrier layer 12D.

As described above, the TFE structure 10D and the OLED display deviceincluding the TFE structure 10D are produced. In the method forproducing the OLED display device in embodiment 2 according to thepresent invention, an organic barrier layer having a sufficientthickness is once formed and then ashed to have a desired thickness.This does not require a resin material to be located locally unlike themethod described in Patent Document 2 or 3. Therefore, the processmargin is large and the mass-productivity is high.

As described above, the surface of the organic barrier layer 14D isoxidized. Therefore, the surface of the organic barrier layer 14D ishighly adhesive with the first inorganic barrier layer 12D and thesecond inorganic barrier layer 16D, and has a high level ofmoisture-resistance reliability. For example, the WVTR of the TFEstructure 10D described above in a specific example (except that theOLED 3 was replaced with a polyimide film having a thickness of 15 μm)was evaluated. The WVTR was less than 1×10⁻⁴ g/m²·day, which is thelowest possible measurable level as converted into room temperature.

In the case where the organic barrier layer 14D is provided betweensubstantially the entire flat portions of the first inorganic barrierlayer 12D and the second inorganic barrier layer 16D, the bendingresistance is high.

The inorganic barrier layers may each be, instead of an SiN layer, anSiO layer, an SiON layer, an SiNO layer, an Al₂O₃ layer or the like. Theresin used to form the organic barrier layer may be, instead of anacrylic resin, a photocurable resin such as a vinyl-containing monomeror the like. Alternatively, an ultraviolet-curable silicone resin may beused as the photocurable resin. A silicone resin (silicone rubber) hascharacteristics of having a high visible light transmittance and a highclimate resistance, and not being easily yellowed even after being usedfor a long time. A photocurable resin that is cured by visible light maybe used. The viscosity of a photocurable resin used in an embodimentaccording to the present invention at room temperature (e.g., 25° C.),before the photocurable resin is cured, preferably does not exceed 10Pa·s, and especially preferably is in the range of 1 to 100 mPa·s asdescribed above.

In each of the above-described embodiments, a display device is producedas an example of organic EL device. The present invention is alsoapplicable to production of an organic EL device other than the displaydevice, for example, an organic EL illumination device. The substrate isnot limited to a flexible substrate but may be formed of a highly rigidmaterial. The display device is not limited to being of a small ormiddle size, but may be of a large size for a large-screen TV.

INDUSTRIAL APPLICABILITY

An embodiment of the present invention is applicable to an organic ELdisplay device, especially, a flexible EL display device, and a methodfor producing the same.

REFERENCE SIGNS LIST

-   -   1: Substrate    -   2: Back plane circuit    -   3: OLED    -   4: Polarization plate    -   10, 10A, 10D: Thin film encapsulation structure (TFE structure)    -   12, 12A, 12D: First Inorganic barrier layer (SiN layer)    -   14, 14A, 14D: Organic barrier layer (acrylic resin layer)    -   14Da: Opening of the organic barrier layer    -   14Db: Solid portion of the organic barrier layer    -   14Ds: Surface of the organic barrier layer (after ashing)    -   14Dsa: Surface of the organic barrier layer (before ashing)    -   16A, 16D: Second inorganic barrier layer (SiN layer)    -   16Da: Void    -   16Dd: Recessed portion    -   20 Element substrate    -   26: Acrylic monomer    -   26 p: Vapor-like or mist-like acrylic monomer    -   100, 100A: Organic EL display device    -   210: Chamber    -   212: Stage    -   220: Shower plate    -   222: Through-hole    -   224: Gap    -   230: Light source device    -   232: Laser beam    -   234: Partition wall

1. A method for producing an organic EL device, comprising the steps of:providing an element substrate comprising a substrate that includes anactive region and a peripheral region outer to the active region andalso comprising an electrical circuit supported by the substrate, theelectrical circuit including a plurality of EL elements formed on theactive region and a back plane circuit for driving the plurality oforganic EL elements, the back plane circuit including a plurality oflead wires each including a terminal on the peripheral region; andforming a thin film encapsulation structure over the plurality of ELelements in the element substrate and on a part of the plurality of leadwires that is on the active region; wherein the step of forming the thinfilm encapsulation structure includes the steps of: forming a firstinorganic barrier layer over the element substrate; condensing aphotocurable resin in a liquid-state on the first inorganic barrierlayer; irradiating a selected region of the photocurable resin with alaser beam having a wavelength of 400 nm or shorter to cure at least apart of the photocurable resin, thus to form a photocurable resin layerwhile forming an opening in the photocurable resin layer on each of theplurality of lead wires; ashing a part of a surface of the photocurableresin layer to form an organic barrier layer; and forming a secondinorganic barrier layer, covering the organic barrier layer, on thefirst inorganic barrier layer.
 2. The method of claim 1, wherein in thestep of condensing the photocurable resin in the liquid state, thephotocurable resin condensed on a flat portion of the first inorganicbarrier layer has a thickness of 100 nm or greater and 500 nm or less.3. The method of claim 1, wherein the step of forming the organicbarrier layer includes the step of generating the laser beam from laserlight emitted from at least one semiconductor laser device.
 4. Themethod of claim 1, wherein the substrate is a flexible substrate.
 5. Themethod of claim 1, wherein the photocurable resin contains an acrylicmonomer.
 6. A method for producing an organic EL device, comprising thesteps of: providing an element substrate including a substrate and aplurality of organic EL devices arranged on the substrate; and forming athin film encapsulation structure over the element substrate; whereinthe step of forming the thin film encapsulation structure includes thesteps of: forming a first inorganic barrier layer over the elementsubstrate; condensing a photocurable resin on the first inorganicbarrier layer; irradiating a plurality of selected regions of thephotocurable resin with a laser beam to cure at least a part of thephotocurable resin, thus to form a photocurable resin layer; removing anuncured part of the photocurable resin; and forming a second inorganicbarrier layer, covering the photocurable resin layer remaining on thesubstrate, on the first inorganic barrier layer, wherein the pluralityof regions of the photocurable resin are selected such that an activeregion of each of the organic EL devices is enclosed by a region wherethe first inorganic barrier layer and the second inorganic barrier laveare in contact with each other without having an organic barrier layertherebetween.
 7. (canceled)
 8. The method of claim 6, wherein theplurality of regions of the photocurable resin are separated from eachother.
 9. A film deposition apparatus, comprising: a chamber comprisinga stage for supporting a substrate; a material supply device forsupplying a vapor-like or mist-like photocurable resin into the chamber;and a light source device for irradiating a plurality of selectedregions of the substrate supported by the stage with a laser beam;wherein the light source device includes: at least one semiconductorlaser device for emitting the laser beam; and an optical device foradjusting an intensity distribution, on the substrate, of the laser beamemitted from the semiconductor laser device.
 10. The apparatus of claim9, wherein the optical device includes at least one movable mirror forscanning the plurality of selected regions of the substrate with thelaser beam.
 11. The apparatus of claim 9, wherein the light sourcedevice includes a plurality of semiconductor laser devices including theat least one semiconductor laser device, and irradiates the plurality ofselected regions of the substrate with a plurality of laser beamsemitted from the plurality of semiconductor laser devices.
 12. Theapparatus of claim 11, wherein the light source device includes adriving device for moving the plurality of semiconductor laser deviceswith respect to the substrate.
 13. The apparatus of claim 9, wherein theoptical device adjusts the intensity distribution such that at least apart of the photocurable resin condensed on the substrate is not cured.14. The apparatus of claim 9, wherein the optical device includes atransmissive or reflective spatial light modulation element modulatingthe intensity distribution.